My rule of thumb for front derailleurs, after height and adjustment, is to set the limit screws. At first the outer is set to keep the chain from dropping between the large ring and the crank. The inner is set to just clear the chain in its innermost position. Then, starting with a quite slack front cable, I progressively take in cable until I can hit the middle ring consistently. For Shimano and SRAM triples this means the cable stays somewhat slack when on the inner ring.
Only after being able to hit the middle ring from all rear cogs do I start to work on hitting the outer ring, and that involves working mostly with the limit screw and fine-tuning the cable tension.
Sometimes, when a fat seat tub will prevent the front cage from getting in close enough, I cheat a little by rotating the derailleur so the rear of the cage turns in a smidge.